be [prove] a great boon to [for]

• (成为)对...极可感谢的[有用的]东西

be [prove] a great boon to [for]的用法和样例：

例句

1. She is out to do a bit of shopping.
   她出去买点东西。
2. The squirrel kept his hoard in a tree.
   这只松鼠把吃的东西藏在树里。